Explosive material

This article is concerned solely with chemical explosives. There are many other varieties of more exotic explosive material, and theoretical methods of causing explosions such as nuclear explosives and antimatter, and other methods of producing explosions, such as abrupt heating with a high-intensity laser or electrical arc.

High Explosives explode in supersonic reactions and without confinement, are compounds, are initiated by shock or heat and have high brisance (the shattering effect of an explosion).

Note that some explosive materials can fall into either category, according to how they are initiated. For example, nitrocellulose deflagrates if ignited, but detonates if initiated by a strong detonator. Gunpowder burns if uncontained, but will detonate if contained and fired.

They are relatively insensitive and need a great amount of energy to initiate decomposition. They have much more power than primary explosives and are used in demolition. The require a detonator to explode. (Examples: Dynamite, TNT, RDX, PETN, HMX, ammonium nitrate, tetryl, picric acid, nitrocellulose, gelignite). Some secondary explosives are insensitive enough that they can be lit with a match -- or a torch -- and will simply burn like wood; a detonation wave is never formed.

In explosive technology only materials that are exothermic—that is, have a heat of reaction that causes net liberation of heat—are of interest. Hence, in this text, heats of reaction are virtually all positive. Since reactions may occur either under conditions of constant pressure or constant volume, the heat of reaciton can be expressed at constant pressure or at constant volume. It is this heat of reaction that may be properly expressed as "heat of the explosion."